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Pulse and Forage Diseases

Pulse and Forage Diseases. Dr. Mary Burrows Montana State University Bozeman, MT. Bacterial blight of pea. Angular lesions. Ascochyta blight on pea and chickpea. Fusarium root rot of pea. Fusarium solani f.sp. pisi. Constriction. Reddish-brown. Fusarium wilt of pea.

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Pulse and Forage Diseases

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  1. Pulse and Forage Diseases Dr. Mary Burrows Montana State University Bozeman, MT

  2. Bacterial blight of pea Angular lesions

  3. Ascochyta blight on pea and chickpea

  4. Fusarium root rot of pea Fusarium solani f.sp. pisi Constriction Reddish-brown

  5. Fusarium wilt of pea Fusarium oxysporum f.sp. pisi • Resistant varieties • Seed treatment • Rotation

  6. Crown rot symptoms in alfalfa Verticillium, Fusarium, Rhizoctonia, Phytophthora, Pythium, Phoma, Mycoleptodiscus, Stagonospora, and Macrophomina

  7. Crown rot control • Variety selection • Promote vigorous growth with proper fertility and irrigation practices. • Control foliar diseases and insect problems. • Avoid cutting hay when soils are wet. • Avoid heavy grazing. • Control weeds with herbicides and avoid cultivation practices which damage crowns. • Avoid field sites with heavy or poorly-drained soils. • Rotate out of alfalfa for 2-3 years. • Heavy watering in the fall will delay dormancy • Stop watering end of September

  8. Stem nematode in alfalfa • Ditylenchus dipsaci White flagging Stunted plants, shortened internodes Swollen nodes Crinkled leaves (between veins)

  9. Stem nematode on alfalfa • Spread by surface water runoff, irrigation, wind-blown crop debris, infested hay, soil and crop debris clinging to equipment, humans and livestock, and with seed • Prevent introduction of nematodes into a field • Rotate with a non-host (not alfalfa or sainfoin) and control alfalfa volunteers 2-4 years • Some resistant lines (not completely resistant) • Cut infected fields slightly higher and when dry to reduce spread

  10. Boron deficiency in alfalfa • Can result in hollow, corky stems; bushy plant; yellow/reddish leaves • Test soil; apply fertilizer containing boron

  11. Alfalfa mosaic virus • Vectored by aphids • Symptoms masked by heat • Wide host range: most legumes, many weeds, potatoes • Transmitted mechanically and in seed • Makes plants more susceptible to winterkill

  12. Ergot in grasses used for feed/forage • Calviceps purpurea • Sclerotia contaminate seed • Soilborne sclerotia overwinter; viable approximately 3 yr in soil or longer in stored grain • Ascospores dispersed by wind and rain infect florets; conidia formed on ovary surface serve as secondary inoculum • Grain converted into sclerotia • More abundant during moist growing seasons

  13. Ergot history (rye) • 400 B.C. Hippocrates prescribed ergoty grain to “further childbirth” • 1039 St. Anthony’s fire • 1692 Salem witch trials • 1935 LSD was synthesized during research on the active ingredients in ergot • Ergot contains Lysergic acid

  14. Ergoty grain is toxic to animals4 forms of toxicity • Convulsions • Gangrene • Hyperthermia (increased body temperature) in cattle • Agalactia (no milk) and lack of mammary gland development, prolonged gestations, and early foal deaths in mares fed heavily contaminated feed

  15. Ergot toxicity symptomsdepend on: • Type of ergot consumed • Ratio of major toxic alkaloids present in the ergot: ergotamine, ergotoxine, and ergometrine • Frequency and quantity of ingestion • Climactic conditions when ergot was growing • Species of ergot • Other impurities in the grain such as histamine and acetylcholine • Claviceps purpurea is usually associated with gangrenous ergotism

  16. Sample Submission • Accurate Diagnosis depends on a good sample and symptom description Enter sample information into PDIS (Plant Diagnostic Information System)

  17. Samples must contain the right material: an entire plant or several plants if practical Diseases may show up on any part of the plant. Foliage diseases Keep most roots and soil intact if possible Check for injuries, disease on the main stem/trunk

  18. Dead Plants Tell no Tales • Avoid dead plants • Choose plants which show a range of symptoms: moderate to severe

  19. Packaging & Shipping Good Intentions

  20. Actual Results

  21. Packaging and Shipping blunders Soil on foliage during shipping creates “diseases” that were not there when the sample was collected.

  22. Packaging and shipping blunders Sample soup Don’t add water or wrap in wet paper towels

  23. Good Packaging • Plastic bag to keep soil on roots • Dry paper towels to protect leaves from contact with plastic bag

  24. Sample Submission • Try to keep sample as fresh as possible until you can get it to the county agent: refrigerate if possible. • Include photographs illustrating the problem if possible.

  25. http://diagnostics.montana.edu Click on ‘Plant Diseases’

  26. Click on ‘Disease Diagnosis Form’

  27. Disease Diagnosis Form • Print out form • Fill out question-naire with as much detail as possible • Place form in box with sample • Take to County Agent – If Possible

  28. Include photographs illustrating the problem and field patterns if possible.

  29. Communication resources • AgAlerts: PDIS.org, or contact Linnea Skoglund (994-5150 or diagnostics@montana.edu) • Montana Ag Fax: Fax request to 406-994-7600 or send an e-mail to mburrows@montana.edu

  30. Wiki.bugwood.org/HPIPM

  31. Be a First Detector First Detectors are the front line for early discovery of new invasive pests.

  32. Asian long-horned beetleAnoplophora glabripennis (Motschulsky) What is a high risk pest/pathogen? A pest not currently known to occur in the continental United States = exotic Southern bacterial wilt Ralstonia solanacearum A pest with limited distribution in the continental United States, but economically important if it spreads.

  33. Select Agents • Liberobacter africanus, Liberobacter asiaticus (Citrus greening) • Peronosclerospora philippinensis (Philippine downy mildew ) • Ralstonia solanacearum, race 3, biovar 2 (Southern wilt) • Sclerophthora rayssiae var. zeae (Brown stripe downy mildew ) • Synchytrium endobioticum (Potato wart disease) • Xanthomonas oryzae pv. Oryzicola (Rice leaf streak) • Xylella fastidiosa (citrus variegated chlorosis strain)

  34. High Consequence Pests (diseases) of Concern for Great Plains region (some examples) • Wheat: karnal bunt, rice blast, seed gall nematode • Potato: potato wart, golden nematode, pale cyst nematode, potato rot nematode, phytoplasmas, wilt • Stone fruits: plum pox virus

  35. FD Expert lab NPDN lab SPRO/SPHD FD NPDN response detection diagnosis What happens when a high risk pest is found? APHIS & SDAs APHIS

  36. Your role as a First Detector • Receive NPDN First Detector training • Take online modules (http://cbc.at.ufl.edu) • Attend classes like this one • Be alert to the unusual or different • Know how to properly submit a suspect high risk pest or pathogen sample • Know how to maintain chain of custody and communication when submitting a suspect sample • Be placed on a national notification registry of First Detectors if you wish to • Receive pest alerts and other relevant updates

  37. Informational sites • Highplainsipm.org • Greenbook.net: Pesticide labels • NDSU fungicide guide http://www.ag.ndsu.edu/pubs/plantsci/pests/pp622/pp622.pdf • MontGuides: http://www.montana.edu/wwwpb/pubs/indexag.html • Wheat diseases of Montana http://scarab.msu.montana.edu/Disease/DiseaseGuidehtml/

  38. Forage Crop Diseases • Disease triangle • Best management practices • Expected yield hit • What factors would favor/disfavor disease Host Pathogen Environment

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